Transcranial direct current stimulation improves novel word recall in healthy adults.

Abstract

Anodal transcranial direct current stimulation (atDCS) has demonstrated beneficial effects in the language domain for both healthy and brain damaged individuals. The present study provides evidence for the efficacy of atDCS in improvement of associative lexical learning in healthy adults, by developing and employing a novel word-learning paradigm. Participants underwent single sessions of anodal and sham stimulation applied over the left posterior temporo-parietal junction, while learning ambiguous words paired with corresponding dominant, subordinate, and non-word meanings. The ability to recall each paired word was tested on a Cued-Recall task and the ability to recognize acquired non-words amongst distractors was tested using a Recognition task. The results revealed significant atDCS effects for non-word recall compared to sham stimulation in the Cued-Recall task, whilst average correct reaction times were not significantly different between stimulation conditions for the Recognition task. These results provide direct evidence that atDCS strengthens associative links produced between ambiguous words and non-words during initial word retrieval, indicating that these newly acquired words become integrated within participants’ pre-existing linguistic experience. This study contributes important information on healthy language processing and highlights the efficacy of atDCS in improvement of language recovery in clinical domains.